Preferred Posture

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Ergonomics, the science of designing workplaces so they fit the person, can help reduce the stress of the repetitive motions you perform at your job. Try adjusting your office furniture so that you can keep your wrists straight while typing. (Typing with your wrists and elbows lower than your fingers is very stressful for the tendons and can put pressure on the main nerve in your hand.) Position your chair high enough so that your elbows are even with, or slightly higher than, your keyboard while you type.

When using a keyboard refer to the diagram in 'setting up your preferred posture position' for recommended posture. This arrangement will reduce chronic muscle loading and thus fatigue.

The essential elements are:

	the feet are placed flat on the floor or other support with the thighs horizontal;
	weight is taken on the buttocks and upper part of the thighs only;
	the movement of the legs is not restricted;
	there is no pressure at the back of the knees or underside of thighs;
	the body is held comfortably erect with the back supported in the lumbar region;
	the relative height of the seat and the working surface should be so adjusted that the shoulders are relaxed when the hands are resting on the keyboard. The upper arms should hang naturally with the angle between the forearm and upper arm about 90°, and with a minimum of wrist bending;
	the top of the visual display unit screen should be located just below the level of the operator's eyes;
	the source material should be positioned at the same height as the screen and at the same distance from the operator's vision, through the use of a document holder.

Setting up your preferred posture position

1. Set the back rest lumbar support so it supports the natural curve in your back. The same mechanism that adjusts the angle of the back rest also adjusts seat tilt (most people seem to prefer the seat to be horizontal or tilted slightly forward). Do not adjust the chair so you are leaning backwards.
   
   
2. Set your chair height so that your arms make a 90° angle or greater when at the keyboard. If you have a desk with an adjustable keyboard section, adjust it down to achieve the same arm position.
   
   
3. If you do not have a desk with an adjustable keyboard section and after adjusting your chair up your feet are dangling, you need a footrest.
   
   
4. Your eye level should now be just above the top of the screen, if it is too low you need to raise it, using a terminal elevation box or computer arm.

Preferred Posture

Note angles of 90 °between the upper and lower leg and also between the upper arm and forearm.

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Last reviewed: March 2005